fix docs

Author: Baunsgaard

src/main/java/org/apache/sysds/runtime/compress/colgroup/dictionary/IdentityDictionary.java

@@ -60,6 +60,7 @@ private IdentityDictionary(int nRowCol) {
 	 * structure is known to have certain properties.
 	 * 
 	 * @param nRowCol The number of rows and columns in this identity matrix.
+	 * @return a Dictionary instance.
 	 */
 	public static IDictionary create(int nRowCol) {
 		return create(nRowCol, false);
@@ -82,6 +83,7 @@ private IdentityDictionary(int nRowCol, boolean withEmpty) {
 	 * 
 	 * @param nRowCol   The number of rows and columns in this identity matrix.
 	 * @param withEmpty If the matrix should contain an empty row in the end.
+	 * @return a Dictionary instance.
 	 */
 	public static IDictionary create(int nRowCol, boolean withEmpty) {
 		if(nRowCol == 1) {

src/main/java/org/apache/sysds/runtime/compress/colgroup/dictionary/IdentityDictionarySlice.java

@@ -61,6 +61,7 @@ public IdentityDictionarySlice(int nRowCol, boolean withEmpty, int l, int u) {
 	 * @param withEmpty If the matrix should contain an empty row in the end.
 	 * @param l         the index lower to start at
 	 * @param u         the index upper to end at (not inclusive)
+	 * @return a Dictionary instance.
 	 */
 	public static IDictionary create(int nRowCol, boolean withEmpty, int l, int u) {
 		if(u > nRowCol || l < 0 || l >= u)